world-beater vs rival

world-beater and rival both are nouns.

Word	Noun	Adjective	Verb	Adverb
world-beater	Yes	No	No	No
rival	Yes	Yes	Yes	No

As nouns, rival is a hypernym of world-beater; that is, rival is a word with a broader meaning than world-beater:

Other hypernyms of world-beater include challenger, competition, competitor, contender.

world-beater (noun)	rival (noun)
a competitor who holds a preeminent position	the contestant you hope to defeat

world-beater (adjective)	rival (adjective)
	as a rival in a competition

world-beater (verb)	rival (verb)
	be the rival of, be in competition with
	be equal to in quality or ability